Abstract
*Our project is about ( Foundation Design of AlMaslamani Mall) which is located in the village of
Beit Eba – Nablus governorate.
*The total plan area of this mall is about 3500 m2
*The number of stories is 6; 4 stories above the
ground surface & 2 stories are below the ground
surface.
Literature Review
 Site
Investigation is the first important step in any
engineering work ; to determine type & depth of
foundations , to evaluate bearing capacity , to identify
construction methods & for many things…
 Foundations
are the part of an engineered system to
receive & transmit loads from superstructure to the
underlying soil or rock .
 There
are two types of foundations : shallow & deep
foundations.
 Many
factors should be taken into consideration in
choosing foundation types such as soil properties ,
economic factors, engineering practice, ....etc
Isolated
footings
Piles
Combined
Foundations
Mat
Isolated Footings

Are used to support single
columns.

This is one of the most
economical types of footings and
is used when columns are spaced
at relatively long distances.
 Its
function is to spread the
column load to the soil , so
that the stress intensity is
reduced .
Mat or Raft Foundations
 are used to spread the load
from a structure over a large
area, normally the entire are
of the structure .
They often needed on soft
or loose soils with low
bearing capacity as they can
spread the loads over a larger
area.
They have the advantage of
reducing differential
settlements.
Combined Foundations
Are used in the following cases:
•
1) When there are two columns so
close to each other & in turn the
two isolated footing areas would
overlap.
•
2) When the combined stresses
are more than the allowable
bearing capacity of the soil.
•
3) When columns are placed at the
property line.
Strap or Cantilever Footings
 Cantilever footing
construction uses a strap
beam to connect an
eccentrically loaded column
foundation to the foundation
of an interior column .
 Are
used when the allowable
soil bearing capacity is high,
and the distances between
the columns are large .
Pile Foundations
 They
are long & slender
members that are used to carry
& transfer the load of the
structure to deeper soil or
rocks of high bearing capacity,
when the upper soil layer are
too weak to support the loads
from the structure.
 Piles
costs more than shallow
foundations; so the
geotechnical engineer should
know in depth the properties
& conditions of the soil to
decide whether piles are
needed or not.
Classification of the piles

According to load transmission & functional behavior :
1) End / Point bearing piles
2) Friction piles
3) Compaction piles

According to type of material:
1) Steel piles
2) Timber piles
3) Concrete piles
4) Composite piles

According to effect on the soil:
1) Driven piles
2) Bored piles
Bearing Capacity & Settlement

Bearing Capacity : is the ability of a soil to support the loads applied
to the ground . Ultimate bearing capacity is the theoretical maximum
pressure which can be supported without failure; Allowable bearing
capacity is the ultimate bearing capacity qu divided by a factor of
safety (F.S).

There are three modes of failure that limit bearing capacity: general
shear failure, local shear failure, and punching shear failure.

Any structure built on soil is subject to settlement. Some settlement is
inevitable, & depending on the situation, some settlements are
tolerable.

When building structures on top of soils, one needs to have some
knowledge of how settlement occurs & how fast settlement will occur
in a given situation.
Geotechnical Investigation
The studied area is
approximately flat with slight
difference in the three existing
elevations. The general soil
formation within the depths of the
borings consists mostly of wadi
deposits of boulders & silty clay
followed by successive layers of
hard boulders mixed with very
little filling silty clay. The whole
site is covered by grass.
The geotechnical engineer
decided to drill four boreholes
trying to cover the whole
construction area.
 The depths of the drilled boreholes were as follows:
Borehole No.
Location
Depth (m)
1
South-west
7.0
2
East
7.0
3
West
6.0
4
North
10.0
Summary of lab. test results:

= 20 KN/m³
w = 7.6 % (avg.)

C = 0 KN/m² (average)
LL = 44.5 %

Ø = 25 º
PI = 25

qall. = 3.0 kg/cm2
G = 2.73

a-Coefficient of active earth pressure: KA = 0.405

b- Coefficient of passive earth pressure: KP = 2.464

c- Coefficient of pressure at rest: Ko = 0.577

After doing check on the bearing capacity value using FOUND
software by using Terzaqi and Meyerhoff formulas, the value
was ranging between 3.2 and 4.3 Kg/ cm2 respectively, SO we
decided to use a value of 3.5 Kg/ cm2 in our project.
Load Calculations
Column #
Footing #
C21 ,C28
F1
Ultimate Load
(ton)
60
Service Load
(ton)
44.5
C8 ,C9
F2
120
89.0
C3 ,C38
F3
183
135.7
C1,C2,C7,C23,C30,C32
,C43
C10,C15,C31,C37,C39,
C4,C16
C5,C6,C22,C29,C33,
C41,C42,C24,C36,C40
C11,C12,C13,C14,C17,
C34,C35
C18,C19,C20,C25,C26,
C27
F4
243
180.3
F5
347
257.4
F6
388
287.8
F7
522
387.2
F8
579
429.5
Isolated Footing Design

1)
2)
3)
4)
5)
6)
7)
8)
9)
Manual Design steps:
Area of footing = Total service loads on column / net soil pressure
Determine footing dimensions B & H .
Assume depth for footing.
Check soil pressure.
Check wide beam shear : ΦVc > Vult
Check punching shear : ΦVcp > Pult, punching
Determine reinforcement steel in the two directions.
Check development length .
Check load transfer from column to footing .
Then, we compare manual design with SAP design in footings F4 & F8 .
 The solution of SAP is always smaller than manual one,
since SAP uses Finite Element Method.
 There
is no need to calculate the settlement of the
isolated footings; since the soil is gravelly soil , & has a
qall. of 3.5 kg/cm2 .
 The
final results of isolated footings design are in the
next table :
Column #
C21 ,C28
F#
Columns Dimension
( m)
H
(m)
B
(m)
Depth
(m)
As , H
(mm2)
As , B
(mm2)
F1
D= 0.5m
1.1
1.1
0.4
816
816
0.5*0.2
C3 ,C38
F2
F3
1.6
2
1.6
2
0.5
0.45
1548
1710
1548
1710
C1,C2,C7,C23,
C30,C32,C43
F4
2.5
2.5
0.52
2614
2614
2.85
2.85
0.90
5330
5330
3
3
0.80
4930
4930
3.5
3.5
0.90
6540
6540
3.8
3.8
0.95
7530
7530
C8 ,C9
C10,C15,C31,
C37,C39,C4,
C16
C5,C6,C22,C29,
C33,C41,C42,
C24,C36,C40
C11,C12,C13,
C14,C17,C34,
C35
C18,C19,C20,
C25,C26,C27
F5
F6
F7
F8
C3 : 0.7*0.4
C38 : D = 0.8 m
C1, C2, C30 : 1.1*0.4
C7: 0.65*0.3
C23 : 0.75*0.75
C32 : 0.8*0.8
C43 : 0.6*0.3
C10 : 0.75*0.75
C15 , C37 : 0.6*0.3
C31 : 1.1*0.4
C39 : D=0.8m
C4 : 0.4*0.65
C16 : 0.75*0.75
C5,C6,C40,C41,C42 : 0.8 * 0.65
C22 , C29 : 0.6*0.3
C24 : 0.75*0.75
C33 : 1.1*0.4
C36 : D=0.8 m
C11,C12,C13,C14,C35: D= 0.8 m
C17 , C34 : 0.75*0.75
C18,C19,C20,C26,C27: D=0.8 m
C25 : 0.8*0.8
Wall Stair Footing
Dimensions and Reinforcement Details
of Wall Stair Footing
Depth of wall footing = 60 cm.
Width of wall = 20 cm.
Width of footing (B) = 2 m.
Reinforcement:
6 φ16 / m in short direction
14 φ16 in long direction
Elevator Wall Footing
Dimensions and Reinforcement Details of
Elevator Wall Footing
Depth = 33cm, h=40cm
Reinforcement details for elevator wall :
4 φ16 / m
For positive moment & negative moment
In both directions.
Pile Foundation
Design of pile foundation
1-Estimating pile capacity
 The
ultimate carrying capacity is equal to the sum of
the ultimate resistance of the base of the pile and the
ultimate skin friction over the embedded shaft length
of the pile, this expressed by :

Qu = Qp + Qs
2-Determination of the point bearing capacity
For piles in rocky sand soil as in our
case , the point bearing capacity
may be estimated as :
QP = Ap q' Nq* ≤ Qlimit
Where:
Ap : Area of the pile tip.
q’ : effective stress at pile tip.
Nq*: Factor depends on soil friction angle
Qlimit =(0.5 Pa Nq* tan Ø ) Ap
3-Determination of skin resistance
It can be calculated by using the following formula:
QS =∑ {P*∆L*f }
Where:
∆L : Length of the pile
P : Perimeter of the pile
f : Frictional factor
The following table presents the dimensions of piles and
their capacities in (KN).
length
(m)
D(m)
8
10
12
14
15
16
18
0.5
122
164
216
278
312
349
430
0.6
157
208
271
345
386
430
526
0.7
196
256
329
415
463
514
627
0.8
239
307
390
489
544
602
731
0.9
285
362
455
566
628
694
839
1
335
420
524
647
716
789
951
Summary of piles sizes, number of piles needed, cap dimensions:
4
Cap
dimension
(m)
2.2×2.2
(14 , 0.5)
4
2.2×2.2
1357
(16 , 0.5)
4
2.2×2.2
1+2+7+23+30+32
+43
(F4)
1803
(15 , 0.7)
4
2.85×2.85
10+15+31+37+39
+4+16
(F5)
2574
(15 , 0.7)
6
4.6×2.85
5+6+22+29+33+41
+42+24+36+40
(F6)
11+12+13+14+17
+34+35
(F7)
2878
(14 , 0.8)
6
5.2×3.2
3872
(14 , 0.8)
8
7.2×3.2
18+19+20+25+26
+27
(F8)
4295
(15 , 0.8)
8
7.2×3.2
Column #
21+28
(F1)
Service Load
(KN)
445
8+9
(F2)
890
3+38
(F3)
Pile size
(L,D)
(m,m)
(8 , 0.5)
# of piles


The structural pile design depends on the nature of soil, which is
either stiff or weak, the pile is to be designed as short column if the
soil is stiff , and designed as along column if the soil is weak.
The minimum area of steel is 0.5% of the gross area of the pile,
also the ties are used starting with 5 cm spacing and ending by 30
cm spacing .the concrete cover must be not less than 7.5 cm.
Asmin=0.005Ag
Efficiency of pile group
The efficiency of the load-bearing capacity of a group pile may be defined
as:
M= Qg(u ) / ∑Qu
Where:
Qg(u)= ultimate load bearing capacity of the group pile.
Qu= ultimate load-bearing capacity of each pile without the group effect

Using simplified analysis to obtain the group efficiency as shown in the following
formula:
ζ = (2(m+n-2) + 4D) / (p×m×n)
Where:
m: # of piles in the direction of Lg.
n:# of piles in the direction of Bg.
d: Spacing between piles centers.
D: Diameter of the pile
P: Perimeter of pile cross section

Design of a pile cap:




The minimum distance between two piles is 3D.
Pile caps should extend at least 15 cm beyond the outside face of exterior
face of exterior piles.
The minimum thickness of pile cap above pile heads is 30 cm.
The cover in pile caps commonly ranges between 20 & 25 cm .
Design Steps:
1) Assume depth (d)
2) Check Punching shear : ΦVcp > Vult, punching
3) Check wide beam shear : ΦVc > Vult
4)
5)
Calculate area of steel needed
Check ρmin. < ρ < ρmax.
Retaining Wall Design:
The retaining wall is designed by PROKON Program :
Conclusions:
1) From soil report, we note that PI is 25 and cohesion is zero and this
can be explained by the following:
We have soil contains some clay between gravels, and when we take a
sample of this soil to be tested for atterberg limits to determine PI,we
use sieve #40 and we take the passing which are clay particles and in
turn this leads to increase the magnitude of plasticity index.
Cohesion is zero since the soil sample is almost gravel.
2) After designing the two alternative choices (single footings and piles
system) & surveying the quantities for concrete only, we find that it is
more practical, realistic and economical to use single footings
3) there is no need to make settlement calculations for footings and
piles ,since we have a gravely soil with B.C of 3.5 kg/cm2(the
settlements in our situation are tolerable, so we can ignore them)..